Blake, A. OMS-III

Abstract:
Bacterial endocarditis is a life-threatening, deadly infection that impacts the lives of several people each year in both developed and developing countries. Although the recognition, diagnosis, and treatments have improved, the mortality rate remains concerning. It is vital to recognize presenting signs and symptoms to ensure early diagnosis and treatment.

A 58-year-old Caucasian male presented to his primary care physician with two weeks of low-grade fevers and severe back pain without an inciting event. He was started on oral levofloxacin, which improved the fevers, but not the pain. He was then sent to the emergency department where he had normal vital signs and unremarkable labs and imaging. Given the reports of daily fevers, blood cultures were drawn and he was discharged home before they resulted. The following day, his blood cultures grew enterococcus faecalis and he returned to the hospital. A transthoracic echocardiogram was performed and showed thickening of the aortic valve leaflets suggestive of endocarditis. Repeat CT and MRI revealed early osteomyelitis and a psoas abscess. He was treated with IV ampicillin and ceftriaxone.

This case demonstrates the importance of employing a team approach to recognize the risk factors and non-specific presentations of bacterial endocarditis, ensuring that necessary diagnostic tests are completed. Early diagnosis and treatment can prevent complications from the infection, and even death.

Introduction:
Bacterial endocarditis is an uncommon, yet dangerous infection that impacts the lives of two to eight people per 100,000 each year.¹ In the United States, this number rose to 15 per 100,000 people between 2000 and 2011.¹⁴ Although there have been advancements in diagnostics and therapeutics, the in-hospital mortality rate remains at about 24%.⁴ Patients who are male, of advanced age, have a history of IV drug use, significant cardiac history, and recent dental procedures or infections are at greatest risk for developing endocarditis.¹⁴ Presentations can be non-specific, but fevers and cardiac murmurs are the most common signs. Less common signs include, but are not limited to, Janeway lesions, Osler nodes, Roth spots, and complications from the primary illness.¹³

Several studies are needed to make the diagnosis of infective endocarditis. Blood cultures must be obtained prior to empiric antibiotic treatment.¹⁶ The causing organism is identified after collecting blood cultures in 90% of patients, with the most common organisms seen being staphylococci, streptococci, and enterococci.^{9, 13,14} An echocardiogram should also be completed. After these tests are completed, the results are compared to the modified Duke criteria to rule in or rule out endocarditis.^{6, 13} Other tests such as CT, EKG, and MRI may be ordered to assess for complications such as heart failure, embolization, neurologic problems, renal failure, and vertebral osteomyelitis.^12,13 These complications can lead to prolonged hospital stays, necessitating aggressive treatment, and increase the chance of death.

Case:
A 58-year-old Caucasian male with past medical history of testicular Hodgkin’s lymphoma, asthma/COPD, obesity, obstructive sleep apnea, eczema, and osteoarthritis reported two weeks of fevers and severe back pain to his primary care physician. His medications at the time included albuterol, montelukast, Symbicort, dupixent, tamsulosin, and testosterone injections. The testosterone injections for hypogonadism were started one week prior to the onset of symptoms. His family history was noncontributory to the case. He denied illicit drug use, alcohol use, and cigarette smoking.

The patient explained to his primary care physician that he had been experiencing two weeks of nightly fevers under 102^° F and worsening back pain, which came on suddenly and was not preceded by injury. He tried using a muscle relaxer, with no improvement in his pain. He also had a cough that was originally thought to be related to his COPD. His doctor suspected a possible pneumonia and prescribed oral levofloxacin, which resolved the fevers but did not alleviate the back pain. He was advised to go to the emergency department for evaluation given his history of cancer and fever of unknown origin.

While in the emergency department, he was afebrile and exhibited normal vital signs. On physical exam, he had tenderness over the lumbar spine and bilateral paraspinal muscles. He was treated with Dilaudid, Valium, and Toradol, which improved his back pain. His labs were significant for elevated neutrophils at 83.1, low lymphocytes at 10.5, elevated bilirubin at 1.3, elevated ALT at 38, elevated sed rate at 49, and mild normocytic anemia. Blood cultures were obtained due to the patient’s reported recent fever. An MRI of his spine was completed and showed fatty marrow replacement of L3 through the sacrum, marrow edema in the anterior aspect of L4 vertebral body on the left, and a possible recent fracture. There were no findings suggestive of osteomyelitis or malignancy within the lumbar spine. Thus, a CT scan was recommended for further evaluation. The CT was normal except for evidence of degenerative changes. With this insignificant work up and improvement in back pain, the patient was discharged home and scheduled to be evaluated by an orthopedic spine specialist for the next day.

However, before seeing the spine specialist, the patient’s blood cultures grew gram positive cocci in chains. He was called to return to the emergency department. On arrival, he was afebrile with stable vitals. His labs were significant for a negative troponin and an EKG with no signs of ischemia. A transthoracic echocardiogram (TTE) showed severe focal thickening of the aortic valve leaflets (0.7 cm of noncoronary leaflet and 0.9 cm of the right coronary leaflet) and moderate to severe aortic insufficiency with multiple jets suggestive of endocarditis. The infectious disease team was consulted and the patient was diagnosed with definite endocarditis according to the Duke criteria. The infectious disease team recommended repeat blood cultures and initiation of IV vancomycin and ceftriaxone for broad-spectrum coverage. Final cultures grew high grade enterococcus faecalis and the patient’s antibiotic regimen was changed to IV ampicillin and ceftriaxone for six weeks. A repeat CT showed new fat stranding in the anterior aspect of the left L3/L4 intervertebral disc space. A repeat MRI was recommended in 24-48 hours because early discitis could not be ruled out. This repeat MRI showed a 17 mm collection involving the medial aspect of the psoas muscle and a hyperintense signal at the left anterosuperior aspect of the L4 vertebral body, suspicious for early osteomyelitis. Prior to discharge, a PICC line was placed to allow for continuation of IV treatment in the outpatient setting. The patient was scheduled with his primary care physician, cardiology, infectious disease, and gastroenterology. It was also recommended that weekly labs are drawn consisting of CBC, BMP, LFTs, CRP, and ESR during treatment. Finally, a repeat CT of the abdomen and pelvis was ordered for four weeks after discharge to ensure that the psoas abscess and vertebral osteomyelitis were resolving.

Four weeks later, the repeat CT of the abdomen and pelvis was completed and did not show any evidence of a psoas abscess or osteomyelitis. The patient was also seen by his gastroenterologist to evaluate for possible GI causes of enterococcus faecalis endocarditis and scheduled for a colonoscopy to rule out malignancy. After completing his 6 weeks of antibiotic treatment, he had a repeat TTE to evaluate for cardiac damage which showed mild to moderate aortic valve thickening, aortic regurgitation, and aortic sclerosis without stenosis. Compared to the previous TTE, the aortic valve was not as thickened, and the aortic insufficiency improved. The patient recovered well and he did not develop further complications from this life-threatening infection 6 weeks after diagnosis.

Discussion:
This case of enterococcus faecalis endocarditis demonstrates the importance of recognizing the risk factors and uncommon presentations of the infection. This patient was a male in his late fifties, putting him at an increased risk for developing endocarditis given that the male to female ratio for bacterial endocarditis is 1.7:1 and the average age for diagnosis is 60 years old.^{3, 7, 14} Although the patient had some risk factors, he did not have a history of recent dental procedures, genitourinary procedures, or any cardiac problems. His only medical procedure around the time of infection was an intramuscular testosterone injection in the buttocks. Notably, the patient reported two weeks of fevers that resolved days prior to being seen in the hospital, and fevers are seen in about 90% of patients with endocarditis.¹³ On arrival to the emergency department, the patient’s only complaint was severe back pain, which is seen in about 15% of patients with endocarditis.¹² Of these individuals, only 2% developed septic discitis or vertebral osteomyelitis, which was a complication seen with this patient.¹²

Diagnostic testing is crucial in making the diagnosis of endocarditis because clinical presentation can vary greatly from patient to patient and blood work is often nonspecific.¹³ This patient’s labs revealed only an elevated sed rate and normocytic anemia, but he had positive blood cultures for enterococcus faecalis. Enterococcus faecalis is the third most common organism for endocarditis, which prompted the need for a TTE in this case.⁵ About 26% of patients with enterococcus faecalis bacteremia will be diagnosed with definite endocarditis.⁵ The valves most commonly affected by this infection are the mitral and aortic valves.^{9, 10} In addition to positive blood cultures, this patient’s TTE showed vegetations on his aortic valve making this a definite case of endocarditis based on the Duke criteria.^{6, 13} Echocardiograms have been found to be very important in diagnosing endocarditis. About 73% of patients with clinical suspicion of endocarditis have vegetations identified on echocardiogram, making this a very sensitive and specific test.¹⁵ Knowing which organism is causing the infection and the degree of damage to the heart valves allows for the prescription of effective antibiotics and consideration for surgical treatment.

If endocarditis is not diagnosed and treated early, many complications can arise such as heart failure, embolization, renal failure, and vertebral osteomyelitis.^12,13 More specifically, 50% of people experience cardiac complications, 13-44% have an embolization, 35% experience neurologic symptoms, and 33% have acute renal failure.¹³ The musculoskeletal system can be impacted as well. Vertebral osteomyelitis should be suspected in a patient with back pain.¹³ Around 51% of patients with endocarditis die within 36.6 months following diagnosis.² In this case, the patient was diagnosed promptly and suffered from early vertebral osteomyelitis and a psoas abscess. Luckily, these complications resolved within a month of IV antibiotic treatment. He followed up with his primary care, infectious disease doctor, cardiologist, and gastroenterologist. He was seen by a gastroenterologist because of the reported correlation between enterococcus faecalis endocarditis and colorectal cancer.⁸ 50% of individuals with enterococcus faecalis endocarditis with an unknown cause of infection have been found to have colorectal cancer.¹¹ This case shows that endocarditis is a complicated infection that encompasses several medical specialties and must be treated by a diverse team of health care providers.

Conclusion:
Bacterial endocarditis can be a fatal, but curable disease if diagnosed early and treated quickly. The presentation of the infection can be very non-specific which makes it difficult to recognize, thus it is extremely important to know both the risk factors and uncommon signs and symptoms. If diagnosed and treated early, complications from the disease can be resolved, monitored, or even prevented. Furthermore, diagnosis and treatment of endocarditis involves a team approach. Primary care physicians advise patients with these symptoms to go to the emergency department where vital tests are obtained based on the presentation. Finally, consultation with several specialties such as cardiology, infectious disease, nephrology, neurology, and orthopedics is necessary to manage the variety of complications that can arise from endocarditis.

Keywords:

• Endocarditis
• Enterococcus faecalis
• Osteomyelitis
• Fever of unknown origin
• Back pain
• Emergency Medicine
• Cardiology
• Infectious Disease
• Gastroenterology

References:

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